Various proposals have heretofore been made to provide structures for installation in a sink drain to prevent items such as tableware, cutlery or the like from being washed into a garbage disposal unit during drainage of the sink. Examples of such structures are those shown in U.S. Pat. Nos. 3,742,524; 4,134,162; and 4,301,557. Another device shown in U.S. Pat. No. 4,519,102 provides for a sleeve having a shoulder in which slots are formed in the base of the sleeve and through the shoulder area which is intended to rest on the mouth of the sink drain flange. All of these prior art structures have suffered from problems such as insufficient flow of water into the drain due to clogging or in some cases due to insufficient area of openings in the design.